Gotten completely lost in an abandoned building with 〜ちゃう
Grammar Explanation: Doing completely or ending up doing with 〜てしまう and 〜ちゃう

During training, Akari spots her company’s feline president, President Aria, sailing by in a small gondola. She instructs Aika to row the training gondola in the same direction, and the two follow him down an alley that’s normally gated from entry. The two lose sight of Aria and find themselves going in circles through flooded abandoned buildings. After some time, Aria’s gondola floats by.
- 灯里:
- 「よかったあぁーーーーー! 私達
( 迷子( になっちゃってたんですよぉ」- “Oh, thank goooodness! We had gotten completely lost, you know!”
Key Points
迷子
( になっちゃってた = had gotten lost”迷子
( になる means “to become lost”.なっちゃって is the casual spoken form of なってしまって, adding the sense that Akari and Aika ended up in an unwanted situation.
なっちゃってた contracts なってしまっていた: they became lost, and that lost state continued until President Aria appeared.
んです makes it an explanation
たんです is たのです in casual explanatory form, giving the reason for her huge relief: “we had gotten lost, you see.”
See Also
- Grammar: Reasoning with 〜のだ